• Title/Summary/Keyword: enclosed

Search Result 809, Processing Time 0.021 seconds

An Experimental and Numerical Study on Fire Suppression Using a Mid-low Pressure Water Mist in a Carriage Fire (중저압 물분무를 이용한 객차내 화재진압에 관한 실험 및 수치해석적 연구)

  • Roh Jae-Seong;Yang Seung-Shin;Kim Dong-Hyun;Jung Woo-Sung;Jang Yong-Jun;Ryou Hong-Sun
    • Journal of the Korean Society for Railway
    • /
    • v.9 no.3 s.34
    • /
    • pp.291-297
    • /
    • 2006
  • The present study investigated the effect of fire suppression using a mid-low pressure water mist in a carriage fire. The fire extinguishing time and temperature distributions below ceiling in the enclosed compartment of $2.9m{\times}2.8m{\times}5.0m$ were measured by stopwatch and k-type thermocouples for various fire positions. The numerical simulations were extensively performed using. Fire Dynamics Simulator(FDS, Ver. 4.0) code and the predictions were compared with experimental data. The prediction results showed good agreement with the measured maximum temperature in the all cases. Whereas the predicted temperature was about $40^{\circ}C$ higher than the measured one after operating of water mist. The predicted fire extinguishing times were compared with those of measured data. Fires are extinguished within 200 seconds at the experiment in Case 2 and Case 3. But in Case 1 fire was not extinguished in the numerical simulation. The reason of the discrepancy between predicted and measured data was that a simple suppression algorithm has been implemented in FDS. Also, various databases of fire properties for combustible materials and more elaborate model considering the water mist were required fur better predictions of the cooling and suffocation effect.

Magma Pathway of Alkali Volcanic Rocks in Goseong, Gangwon-do, Korea (강원도 고성지역에 분포하는 알칼리 현무암질 마그마의 상승경로)

  • Kil, Young-Woo;Shin, Hong-Ja;Ko, Bo-Kyun
    • The Journal of the Petrological Society of Korea
    • /
    • v.16 no.4
    • /
    • pp.196-207
    • /
    • 2007
  • Miocene basalt plugs in Goseong contain a large variety of crustal and mantle xenoliths and xenocrysts. One of basalt plugs, Unbongsan, are derived from 160 km depth. Whole-rock geochemistry and pressure and temperature conditions of mineral phases indicate that Unbongsan volcanic rocks are alkali basalts and the source magma of the alkali basalts was generated from about $0.2{\sim}2%$ partial melting of depleted garnet peridotite. Crystallization pressures and temperatures of mineral phases within ascending magma of Unbongsan alkali basalt indicate that olivines, clinopyroxenes, and plagioclases were crystallized at $75{\sim}110km,\;40{\sim}52km,\;37{\sim}54km$ depth, respectively. The ascending magma of Unbongsan alkali basalts enclosed mantle xenoliths at about $57{\sim}67km$ depth.

Depositional Processes of Fine-Grained Sediments and Foraminiferal Imprint of Estuarine Circulation by Summer Floods in Yoja Bay, Southern Coast of Korea

  • Lee, Yeon-Gyu;Jung, Kyu-Kui;Woo, Han-Jun;Chu, Yong-Shik
    • Journal of the korean society of oceanography
    • /
    • v.35 no.2
    • /
    • pp.109-123
    • /
    • 2000
  • Depositional processes of fine-grained sediments were investigated on the basis of sediment transport vector analysis and identification of benthic foraminiferal assemblages in Yoja Bay, southern coast of Korea. The bay is a semi-enclosed embayment where extensive mud flats occur with a width up to about 4 km. Most surface sediments are poorly sorted (sorting values: 1.9-3.0 ${\phi}$) mud and silt (mean grain size: 6.0-8.7 ${\phi}$), except for the tidal inlets with basement rocks locally exposed. Grain-size distribution shows a fining tendency toward the basin center near the Yoja Island, implying a possible existence of turbidity maximum and relatively rapid settling of fine-grained sediments. The agglutinated foraminiferal taxa are dominant in the inner bay and decrease in abundance toward the mouth of the bay. Species diversities are higher in the outer bay, due to mixing of the offshore faunas with those of the bay. Four groups of benthic foraminiferal assemblages, identified by cluster analysis, represent the bay. Biofacies I and ll with relatively lower diversities are dominated by Ammobaculites exiguus and Ammonia beccarii, suggestive of influx of fresh water. In contrast, biofacies III and IV with relatively higher diversities include increased amounts of calcareous genus Elphidium and Quinquelocuzina, accounting for strong influence of sea water from the offshore. The fluvial discharge in summer floods appears to develop a bay-wide, clockwise lateral circulation in Yoja Bay, a typical of well-mixed estuaries. Accordingly, the foraminiferal assemblages of the surface sediments well show a sign of this circulation. The dominant inflow of the offshore water into the western part of the bay has resulted in more extensive muddy tidal flats compared to the eastern narrower counterpart.

  • PDF

SEASONAL VARIATION OF THE OCEANIC WATER INTRUSIONS INTO KAGOSHIMA BAY DERIVED FROM THE SATELLITE SST AND CHL-A IMAGES

  • Hosotani, Kazunori
    • Proceedings of the KSRS Conference
    • /
    • 2008.10a
    • /
    • pp.61-64
    • /
    • 2008
  • Seasonal distribution of the oceanic water intrusion was investigated using satellite SST (sea surface temperature) and chl-a (chlorophyll-a) images taken by the MODIS Aqua sensor. The warm water mass emanating periodically from the meandering Kuroshio Current brings the oceanic water intrusion, known as the 'Kyucho' phenomenon, into Kagoshima bay during the winter. Satellite SST images and buoy robot data show that this warm water intrusion has the characteristics of a semigeostrophic gravity current influenced by the Coriolis effect. However, it is difficult to find the oceanic water intrusion during the summer season considering that it is accompanied by thermal stratification, and SST shows almost the same temperature between the inner side of the bay and the ocean. In this research, the satellite chl-a images taken by MODIS Aqua were employed instead of SST images to reveal the oceanic water intrusion in each season. The enclosed bay has the tendency to undergo eutrophication caused by organic materials from land and differences in chl-a concentration of the bay water and the oceanic water. As a result, distribution of low concentration chl-a with oceanic water intrusion in summer season shows almost the same pattern in winter season. On the other hand, in spring season, both SST and chl-a images are available to differentiate the oceanic water intrusion. Therefore, applying the suitable satellite sensor images for each season is effective in the monitoring of oceanic water intrusion. Moreover, in this area, SST and chl-a distribution reveal not only the oceanic water intrusion into Kagoshima bay but also the intrusion at Fukiage seashore facing East China Sea.

  • PDF

Modelling of aluminium foam sandwich panels

  • D'Alessandro, Vincenzo;Petrone, Giuseppe;De Rosa, Sergio;Franco, Francesco
    • Smart Structures and Systems
    • /
    • v.13 no.4
    • /
    • pp.615-636
    • /
    • 2014
  • Aluminium Foam Sandwich (AFS) panels are becoming always more attractive in transportation applications thanks to the excellent combination of mechanical properties, high strength and stiffness, with functional ones, thermo-acoustic isolation and vibration damping. These properties strongly depend on the density of the foam, the morphology of the pores, the type (open or closed cells) and the size of the gas bubbles enclosed in the solid material. In this paper, the vibrational performances of two classes of sandwich panels with an Alulight(R) foam core are studied. Experimental tests, in terms of frequency response function and modal analysis, are performed in order to investigate the effect of different percentage of porosity in the foam, as well as the effect of the random distribution of the gas bubbles. Experimental results are used as a reference for developing numerical models using finite element approach. Firstly, a sensitivity analysis is performed in order to obtain a limit-but-bounded dynamic response, modelling the foam core as a homogeneous one. The experimental-numerical correlation is evaluated in terms of natural frequencies and mode shapes. Afterwards, an update of the previous numerical model is presented, in which the core is not longer modelled as homogeneous. Mass and stiffness are randomly distributed in the core volume, exploring the space of the eigenvectors.

Effects of Light Quantity and Quality on the Growth of the HarmfulDinoflagellate, Cochlodinium polykrikoides Margalef (Dinophyceae) (유해성 적조생물, Cochlodinium polykrikoides Margalef (Dinophyceae) 성장에 영향을 미치는 광량과 파장)

  • Oh, Seok-Jin;Yoon, Yang-Ho;Kim, Dae-Il;Shimasaki, Yohei;Oshima, Yuji;Honjo, Tsuneo
    • ALGAE
    • /
    • v.21 no.3
    • /
    • pp.311-316
    • /
    • 2006
  • The effects of light quality and irradiance on the growth of Cochlodinium polykrikoides were investigated in the laboratory. At 25°C and 30 psu the irradiance-growth curve was described as μ = 0.34 (I-9.76)/(I+12.5), (r=0.98). This suggests half-saturation photon flux density (PFD) (Ks) of 32.0 μmol photons m–2 s–1, and a compensation PFD (Ic) of 9.76 μmol photons m–2 s–1. Because the Ic equates to a depth of ca. 15.4 m, these responses suggest that irradiance at the depth around and below the thermocline in Yeosuhae Bay would provide favorable conditions for C. polykrikoides. Photoinhibition did not occur at 300 μmol photons m–2 s–1, which was the maximum irradiance used in this study. Blue (450 nm), yellow (590 nm) and red (650 nm) light had different effects on the growth of C. polykrikoides: it grew well under blue light, but not under yellow light. This implies that C. polykrikoides is more likely to cause an outbreak of red tide in the open sea where blue-green wavelengths predominate, rather than in enclosed water bodies where suspended particles absorb most of the blue wavelengths, and yellow-orange wavelengths predominate.

Effect of Deoxygenizer on the Suppression of Lipid Deterioration of Boiled and Dried-Anchovy Engraulis japonica

  • JEONG Bo-Young;SEO Hae-Jeom;MOON Soo-Kyung;PYEUN Jae-Hyeung
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.28 no.6
    • /
    • pp.770-778
    • /
    • 1995
  • Anchovy Engraulis japonica boiled and dried was stored at $20^{\circ}C$ for 5 months after that treatment of sodium-erythorbate (Na-ery) or deoxygenizer (Deoxy). During storage, peroxide value (POV), thiobarbituric acid (TBA) value, lipid content, and lipid class compositions were determined to evaluate the quality of the samples. pay was decreased rapidly for the first 3 months storage and its decrease was Deoxy group>Control group>Na-ery group in that order. TBA values increased for the first 4 months and then decreased rapidly, and it's increase was the highest in Control group, followed by Na-ery and Deoxy group. Total lipid contents in all samples declined during storage. Especially, phospholipid decreased mainly in Na- ery and Deoxy group, while neutral lipid mainly in Control group. Triglyceride (TG), phosphatidylethanolamine(PE), and phosphatidylcholine(PC) decreased, while free fatty acid (FFA) and lyso-PC (LPC) increased during storage. The decrease of TG was the highest in Control group and that of PE and PC was higher in Na-ery group than in other sample. The decrease of PE in all samples (except Deoxy group) was higher than that of pc. The increase of FFA and LPC were higher in Control and Na-ery group than in Deoxy group. These results indicated that the lipid deterioration of the boiled and dried-anchovy was effectively suppressed by the enclosed deoxygenizer during storage at $20^{\circ}C$.

  • PDF

Algicidal Effects of a Newly Developed Thiazolidinedione Derivative, TD49, on Dinoflagellate Akashiwo sanguinea (Thiazolidinedione 유도체(TD49) 물질을 이용한 적조생물 Akashiwo sanguinea의 제어)

  • Baek, Seung-Ho;Shin, Hyeon-Ho;Jang, Min-Chul;Kim, Si-Wouk;Son, Moon-Ho;Cho, Hoon;Kim, Young-Ok
    • Ocean and Polar Research
    • /
    • v.34 no.2
    • /
    • pp.125-135
    • /
    • 2012
  • To evaluate the algicidal impact of a newly developed algicide thiazolidinedione derivative, TD49, on dinophyceae Akashiwo sanguinea in aquatic ecosystems, tentative culture experiments for the target species were conducted in small (SS), middle (MS), and large scale (LS) culture vessels. When TD49 was introduced at the final concentration of $2{\mu}M$ in SS and MS, as well as $1{\mu}M$ in LS, the abundance of A. sanguinea decreased significantly in all the treatments. On the other hand, total phytoplankton abundance, except A. sanguinea in the TD49 treatments, gradually increased with culture time, which implies that a cell destruction of A. sanguinea by TD49 is a major cause of the population growth by other phytoplankton species. Also, A. sanguinea was easily destroyed, which was likely to be a source of extracellular substances. In particular, a pH decrease was significant in the treatments than in the control, which indicates that the water in the treatments has been acidified, due to an increase in the heterotrophic metabolisms of bacteria and degradation of A. sanguinea cells. Our results indicate that the TD49 substance is the potential agents for the control of A. sanguinea in the enclosed and eutrophic water bodies.

Arctic Exposure: LOVELAND's Sublime Simulation of an Endless Apocalypse

  • Bishop-Stall, Reilley
    • The Journal of Art Theory & Practice
    • /
    • no.13
    • /
    • pp.185-213
    • /
    • 2012
  • Charles Stankievech's 2011 installation LOVELAND includes a wall-sized screen depicting video footage of a barren arctic landscape in an enclosed room, painted and bathed in white light, that appears as an extension of the imaged environment. A melodic and industrial musical score emanates from multiple sound panels and as the music increases a cloud of purple smoke becomes visible on the horizon line in the distance and gradually advances toward the viewer until it completely fills the screen. The smoke then remains, rushing about madly and lapping at the border between the screen and the room before it suddenly subsides and the spectator is again left with the desolate landscape. The entire process takes a mere five minutes and then, fixed on an endless loop, begins again. This paper positions LOVELAND as an attempt to simulate a sublime experience of the end of the world through a transposition of the Arctic atmosphere into the gallery space. Encompassing a discussion of the historical and contemporary significance of the Arctic in popular culture, aesthetics and environmental politics, it is suggested that Stankievech employs an apocalyptic trope in reference to the unstable position of the North in the current political and ecological climate. Revisiting critiques of modernist exhibition practices and investigating the perceptual and temporal dimensions of the work, this analysis focuses primarily on the experience of the installation's spectator. Visually, aurally and phenomenologically immersed, the viewer is made subject to, and implicated in, the events unfolding on the screen and within the space. Due to the looping of the video footage, this paper argues that the apocalypse imaged in LOVELAND is presented as an endless event - incessantly enacted, yet infinitely deferred - and that the spectator is enveloped in an uncertain and unceasingly extended present moment.

  • PDF

A study on the design of ensemble reflector in a concert hall (콘서트홀 무대반사판의 설계에 관한 연구)

  • Kim, Min Ae;Oh, Yang Ki
    • The Journal of the Acoustical Society of Korea
    • /
    • v.37 no.5
    • /
    • pp.356-362
    • /
    • 2018
  • Stage in classical shoebox type concert hall is placed and occupy one side of the hall and have much early reflections from surrounded walls and ceiling nearby. On the other hand stage in vinyard terrace concert hall, which is surrounded by terrace seats instead of walls and ceiling, has lack of early reflections which may cause lack of communications among the players. Vinyard hall stage is enclosed with terrace seats front walls, while the players located on the stage riser keep the walls off as the walls have limited heights. Ensemble reflector installed above the stage is an effective way for the players to monitor the sound produced on the stage. That may help achieving a good ensemble of the performance. Ensemble reflector over the stage of a large vinyard terrace hall of 2,000 seats was designed with the variables of the location, the shape and the area. The effectiveness of the ensemble reflector is verified with the parameter of stage support.